Electric switch



June 6, 1944. J. s. NuNEs 2,350,965

ELECTRIC SWITCH Filed Jan. 7, 1941 2 Sheets-snapt l Immmlm INVENTOR @sJa//A/ .SIM/M55 #W MORNEYS June 6, 1944. J. s. NuNEs ELECTRIC swITcHFiled Jan. 7, 1941 2 Sheets-Sheet 2 v INVENTOR Jax/v 5. Afm/5 BY 2 'lATTORNEYS Patented June 6, 1944 UNITED STATES ,l PATENT oFFlcE 2,350,966'v l ELECTRIC SWITCH John S. Nunes, New York, N. Y., assig'nor toElizabeth Lefkowitz, doing business as Fulton Elec- V*trie Mfg. Co., NewYork, N. Y.

ApplicationJanuary 7, 1941, Serial No. 373,393

The present invention relates to electric switches of the handoperatedtype, and in particular to switches of the pull-chain type, although theinvention is not limited thereto.

It is the general object of the invention to provide an electric switchof inexpensive, compact and durable construction requiring few parts andcapable -of easy assembly, and which can be readily adapted for use forthe control either of single or of multi-circuit installations in homes,stores, industrial establishments, etc.

-More particularly, it is an object of the invention to provide a switchof the type indicated which can be readily adaptedv for the control ofadditional circuits by the coupling therewith of compact'switch units-ofsimilar construction.

Itis also an object of the invention to provide a switch mechanismhaving a mounting member upon which can be attached, upon both sidesthereof, switch units of the same or of different type and upon whichadditional units may be mounted in coaxial relation `for the control ofadditional circuits, and all operated by one and the same actuatingmechanism.

It is also an object of the invention to provide an improved switch ci.'the rotary type having'a plurality of bridging contact-carrying discsmounted upon a common shaft, and particularly a switch of this kindwherein one or more of the discs oscillate through a more or less fixedangle to effect closing and opening of a circuit during a singleactuation of the switch, whereby the time during which any particularcircuit or circuits remain closed (or open) may be manually controlled,while other circuits connected to the switch are controlled in the usualfashion, that is, are closed and opened only on successive actuations ofthe switch.

One form of apparatus for which switches of the just mentionedconstruction are particularly suited is the now well-knownfluorescentlamp. In the control of uorescent lamps, it is now thegeneral practice to provide such lamps with a thermally controlledlstarter which, upon closing of the lamp switch, controls thepre-heating of the lamp and which, after a more or less fixed timeinterval, automatically breaks the starting. circuit and leaves the lampto be operated by the operating circuit which includes the column ofheated or ionized gas between the electrodes in` side the lamp. Thisthermostatically operated' byinsufllcient pre-heating of the gas, sothat frequently the switch must be QIOSed a second and 50, tion and thefeatures of novelty wil1 be set forth even a third time before steadyoperation of the lamp is obtained. Also, frequent replacementoi rthestarter is usually necessary.

It is accordingly a further object of the invention is'provide a switchof the manually-operated type which is adapted to include, as one of theswitch units thereof, a hand controlled switch assembly acting toreplace the automatic starter heretofore employed with fluorescentlampsand similar apparatus, and through which suilicient pre-heating ofthe gas in the lamps (or other prelliminary regulation of otherapparatus) may be insured by the operator before the starting circuit isbroken.

Another object of the invention is to provide a switch mechanismmanually controlled to time f the operation of any circuit withoutrequiring the frequent replacement common in known thermal switches, andat the same time eliminating the special ceramic support for such knownswitches. It is a still further object of the invention to provide aswitch mechanism composed of a plurality of more or less separate switchunits, each with its own housing or housing section, which are capableof standardization and of being quickly assembled in numerouscombinations to control a z great variety of circuits singly and Aincombination, whereby a minimum of parts and assembled A switches need bekept on hand by the manufacturer for prompt filling of orders callingfor many different combinations of multi-circuit control.

Other objects of the invention are to PIOvide improved mechanism foractuating a rotary switch; to construct a switch controlling aplutrolling two or more electrically operated devices connected in anydesired circuit, as in the form of p two-way, three-way, and four-wayswitches, single pole, multi-pole, etc., and in various combinations; toprovide a timing switch which can be used equally well in A. C. and D.C. vcircuits in contrast to the thermal switch which is suitable for A.C. operation only; and to provide an improved form of rotary bridgemember which insures against accidental breaking of circuits.

Still other objects and advantages of the invention Will appear from thefollowing descripin the appended claims.

The invention will be described in greater detail with the aid of theaccompanying drawings.

wherein Fig. 1 is an elevational view taken along the line of Fig. 2,and looking in the direction of the arrows;

Fig. 2 represents a central vertical section along the line 2-2 of Fig.1;

Figs. 3 and 4 are views taken respectively along the lines 3--3 and 4-4of Fig. 2;

Fig. 5 shows a horizontal section through the switch andis taken alongthe line 5-5 of Fig. 1;

Fig. 6 is a detail showing one form of toothed disc carrying thebridging member and the insulating plate to which it is secured;

Fig. 7 shows the reverse side of the insulating plate and the drivingratchet disc secured thereto;

Fig. 8 is a View of the driving Dawl y Fig. 9 is an enlarged View kinperspective of the mounting member constructed in accordance with.

the invention;

Fig. 10 is a view of another embodiment of my invention showing themanner in which a plurality of similar units may be built upon themounting member for the control `of additional circuits. 'theswitch-being designed for theconparticularly fonthecontrol ofthe-circuitsi'of a fluorescent lamp, freferred to. hereinabove, althoughsuitable for any combinationof timed and non-timed circuits, it will beseen that the-ihousingV is` formed ftwo ymeinbersiZIl .and 2| ofzsim-Vilar construction' and made of vany suitable insulating ImateriaI, suchas` a resinous moulding composition orof porcelain'or the like, The

:housingfsections and 2| are secured upon. op-

posite sides of a mounting member 22, which` may -befmade of metal, suchmember being shown in detail in fFig. 9. This mounting member has avmainportion of more or less U-shape composed of the central plate22aand'the legs 2217. Extending 1inopposite directions from the legs 22hare'pairs-f ears 23, 24 which'are provided with-threadedopenings 25 forapurpose shortly to be described. A'bearing plate Y2| extends from themainplate 22a, more or'less in the same-plane as a pairy ofopp'ositeears23, 24, and is apertured as-shown atg21 for the receptionofthedrivingshaft `V3l). A threaded nipple 28"is'se`cured to the plate 22a,thelatter having an 'openingregister- `ing withthe hollow interior ofthenipple,

.Referring .to jFig. 2,.it willkbe seenV that the housing sectionsEiland 2| aresecured to the mounting memberlzby way of. screws 29. whichpass through'suitable'bores `in thehousing sections and arereceivedwithin the `threaded openings 25. There vis thus provided -a compact'andneat construction -in` which .either vof the 'housings and itsassociated mechanism,4 described below, can'be removed and either suchmechanism, orboththe housingand the mechanism replaced with a unithaving different switch characteristics. l

The driving shaft is mounted for oscillating movement Within the centralopenings in .the

lhousing members20 and 2| and y passes through --tion of the shaft, thecircuits controlled by the Y contacts in such chamber are both made andbroken; while the contacts arranged in the chamvber. 3| is so disposedand operated that successive,con'iplete oscillations are required toeffect closing and opening of the circuits in alternation.

The housing `section 2| (Fig. 1) is provided on its outer face with twopairs of more or less ra- Lill fboard.Vr The-bridginggmember lisVprovided. w'ithra non-circular openingso -as to t snugly'over .the-fend ofthe shaftV and rotate therewith, `It is'Y pro- I'te1 -of-tli eVshaft,V thereby forming four cam sur- 'faces orteeth, therebeingmore orless radially `'the slotsA 33,

dial slots 33 running from the periphery of the housing inwardly tocommunicate with ,the

chamber 32,'the slots beingarranged at 90f in- Vtervalsfas-`illustrated. 'The slots" are designed to receive the 'con'zluctorstf1,34 and 35,35 which are introducedthereintofrom the right as viewedinFig. 12. 'T01I the opposite pairsof conductors '34,.34- andf35, 35,there are's'oldered or otherwise secured, the spring contactsl34a,-34aland 35a, f'35a. `The spring contacts maybe made of phosphor bronze oranyother'v resilient material and are generally of Z-shape, Voneend'being anchored within lateral recesses 36,V communicating 'with Thefree* ends 36a of the spring contacts project into the chamber 32.y

f The shaft 3|) is-ofy non-circular crossesection, preferably square,except forthe portion fournaled in the housing section4 20,` which mayberound. 'Mounted upon the shaftandV within'the chamber 32' isa bridgingmember which includes al disc member Slmade of'suitable linsulatingmaterial, 'such as porcelain, glass, resin,or`ber videdv upon itsperipheral-surfaces withfozurcarlcuate :sections eccentric -withirespect to `th'ejcenextending shoulders `38 between the successivecams'urfaces. Ascari' beseen from Fig. 1, the

4disc 31 Vandthespring contacts 36 are so disposed -`that the free ends,of ,the latter. ride smoothly over the cam surfacesas the member 31 isoscllatledin the v clockwise direction and lthen returned.'- Y A,

vThe bridge memberi31 carries ,tvvoidentical 'bridgingconductorsSS and40 which aresecure- 1y mounted thereon, each beingcomposed of an annularsection IlY whose central opening clears the shaft 3|). The conductorsare provided with diagonally opposite terminal portions 42 overly- `ingthe peripheral cam surfaces of .the bridge vmember'l and extending. in.opposite directions.

It. will be vunderstood that the, member .39 is mounted upon one side ofthe member 31 while the. member 40 is positioned v upon the `oppositesideiof eachmembenrthe terminals on .the mem- Jbers 39 and 40 beingdisplaced by 90.

Asshown in Fig. 1, theoscillating terminals! 42 project beyondtheshoulders 38 and overlie to a certain extent theadjacent cam surface.This projection insures maintenance of Vcontact vwith the terminals36aeven in the Vcase,.ofpexcessive rotation of. the. shaft .and alsoprevents accidental dropping of any lterminal. ontothe next camsurieortooth, `The terminalszfcoveronlyabout Vlocated Within the chamber 3|one-half the peripheral length of each of such cam surfaces, the latterbeing suitably recessed to receive such terminals and'to provide asmooth juncture between the terminal-covered portions of the camsurfaces and the uncovered, nonconducting portions of such surfaces. v

The conductors 34, 34 and 35, 35 are connected to the heating electrodesof different fluorescent lamps and it will be seen that upon rotation ofthe shaft 30 through an angle of about 60 to 90, the opposite pairsv ofterminals 36a will be bridged by the respectivemembers 39 and 40,whereby the circuits to the heating coils of the respective lamps willbe closed, and such circuits will remain closed so long'as 'the shaft isheld in its extreme position of movement. When the lamp has begun toburn steadily, manual release of the switch will cause return of theshaft to the inoperative position shown in Fig. 1 (by a mechanism aboutto be described), whereby the starting circuits will be broken. Thelamps will then be operated by the circuits controlled by the switchmechanism within the housing 28.

Mounted upon the shaft 30 adjacent to the journalled end 30a is abridging member composed of an insulating plate 43 having upon one Asidethereof a driving ratchet wheel 44, whose function will be describedbelow,v and upon the opposite side a toothed Wheel 45 made of anysuitable insulating material. The elements 44 and 45 are secured to thedisc 43 in any suitable manner, as by means of tongues 46 struck fromthe body of the ratchet wheel 44 and passing through suitable openings4in the disc 43 and into the openings 41 in the wheel 45. These partsAare al1 provided with a circular central opening so that they are freeto rotate' upon vand relatively to the shaft 38.

The toothed wheel 45 is provided with cam teeth 48. A conductingmetallic' bridge 49 is secured to the outer face of thel wheel 45 and isprovided with diametrically opposite contact surfaces 0 which are bentover to cover a pair of opposite teeth, the other pair of teeth beinguncovered and thus presenting an insulating surface. As can be seen fromFig. 2, the wheel 45 is of the housing 20. An annular insulating washer5| is located between the housing 20 and the opposite ears 23, 24' ofthe mounting member 22, and in the illustrated construction theinsulated disc 43 is in substantial alignment with the washer 5| withonly a slight clearance therebetween, so that the switch mechanism ofwhich the bridge member 49 forms a part is effectively closed againstand insulated from the driving mechanism described hereinafter.

The housing 20 is provided upon its raised an.- nular surface with twopairs of oppositely disposed slots 52 (Fig. 4), similar in constructionand arrangement to the slots 33 shown in Fig.y l. The slots are adaptedto receive conductors 53 which are connected to spring terminals 54.While only one pair of conductors 53 is shown in Fig. 4, it will beobvious that a second circuit can be controlled by a second pair ofconductors located within the other pair of slots 52, except that thetwo circuits will be controlled in alter'- nation; that is, when one isclosed the other will be open. It will be seen that the washer 5| servesto close the slots 52 and thereby retain the conductors in place and atthe same time insulate the metal contacts against the' metal'mountingmember 22. 'Ihe slots'33 ofthehousing 2| are similarly closed by aninsulating plate 55.

The ratchet wheel 44 constitutes part of the actuating mechanism for theswitch and is arranged to be operated by an oscillating member 51 whichis actuated by a pull-chain 56 of conventional construction. To thisend, the oscillating member 51 is provided with diametrically oppositedogs or pawls 58 which engage within openings 59 spaced 90 apart in theratchet wheel 44. The member 51 is provided with a non-circular centralopening 60 so as to be locked to and thereby rotate with the shaft 30;in other words, the pawl member oscillates through a more or less fixedangle with the shaft. In the position of rest, the pawls 58 are locatedwithin a pair of opposed openings 59; and upon actuation of thepull-chain, the pawls engage the forward wall of each recess and rotatethe ratchet Wheel 44 and parts 43 and 45 'connected thereto through anangle 0f 90.

The oscillating member 51 is provided with a ange 6| which extends firstaxially to provide a supporting surface for' the pull-chain 56 and thenextends radially so as to retain the chain between itself and theratchet wheel 44. The rear-end portion of the flange is provided with ahook member 62 having an open slot 63 which serves for anchoring thechain, the ball at the end of the chain being positioned to rest againstthe shoulder 64 of the hook member 62, the connecting flexible wire ofthe chain passing through the slot 63, and the chain then being passedover the member' 51 and within the flange 6l. Any other suitable mode ofmounting can of course be employed. The flange is interrupted asindicated at 65 to facilitate formation of the pawl 58.

A return spring 66 surrounds the shaft 30 and is connected at one end toa lug 61 struck from the body of the bearing plate 26 of the mountingmember 22 (Fig. 9), while its other end is connected to the V-shapedgroove formed between one of the pawls 59 and an oppositely bent tongue68 on the member 51. If it is desired to vary the tension of the spring,its other end may be connected to the lug 69 on the bearing plate 26.

TheV radius of the outer portion of the hook member 62 is greater thanthe distance between the center of the shaft and the edges 10 (Fig. 3)of the legs 22h of the mounted member. The hook member accordinglycooperates with the edges 10 to limit the movement of the shaft in bothdirections. The length of the legs 22h is so determined that the shaftis given a total angular movement of somewhat more than the excess over90 being the free play of the switch. The switch is shown in Fig. 3 inits unactuated condition in which the hook member 62 bears against edge10 of the lower leg 22b.

The parts may be assembled in the following manner: The shaft 3|! ispassed through the aperture of the bearing plate 26 of the mountingmember 22 and through the central opening of 'the housing 2|, and thetoothed Wheel 31 is then positioned upon the free end of the shaft.After placing the cover plate 55 upon the outer face of the housing 2|,the latter is secured to the opposite ears 23 and 24 of the mountingmember by means of the screws 29. These parts are now firmly connectedwith each other and the partial assembly can be easily handled withoutdanger of displacement of any parts.

The spring 66 is now threaded upon the shaft and one end thereof isengaged with the lug 61 or 69. The oscillating member 51 With thepullchain anchored thereon is now slid upon the shaft in such angularposition that the hook member V62 is located externally of fthe; edges14. Upon engaging the free end of the spring 66 Wit-hin the V-shapedrecess between thetonguei` and the adjacent pawl 58, themember51will beurgedV by the spring into the position shown iin Fig. 3. It will beunderstood that the pull-chain. has been passed through the hollownipple 28.` The assembly composed vof the disc 43, ratchet wheel44 andtoothed wheel 45 is now positioned upon the shaft, and the Washer 5| isarranged with its apertures in alignment with those inthe adjacent ears23 and24. The `housing "20 is now mounted upon the reduced free end 30aof the shaft 3D, and upon insertion and-tighteningof the screws 29, theWhole mechanism is united into a `rigid and compact assembly. It`-willVbe understood that the conductorsf35 and -53 'are-properlyipositionedwithintheir 'respective housings .2l and 20 prior to assembly of theswitch, and that the wheels 31 and 45 are properly positioned-withreference to the cooperating contacts to provide the desired sequenceof-.circuit'closing and opening. The switch can be mounted in anyvsuitable manner and may, for'example, be secured toY a support 1! whichis clamped between athreaded washer 12 and a nut V13,'the latter having"a trumpet-shaped central opening through which the chain passes.

The operation of the above-described mechanism is as follows: l

As has already been'indicated, the oscillating actuating'member 511s, ineffect, locked to Yand rigid with theshaft 3B and the same is'true ofthe toothed wheel 31; The bridging assembly within the housing 20,howevencomposed of the n parts 43, 44, 445 and 49, is free-torotate-upon the shaft. VUpon actuationAV of the pull-chain, therefore.the mechanisms within thehousings ZI Vand 2li will rotate with theshaft, the ratchet wheel 44 being driven '-by thepawls l58 ofthe memberr51. During this movement', the free ends 35a of the contact memberswithin the housing 2l will ride upon the surfaces ofthe teeth until theyengage the conducting members 42. contact members are connected. Wherevthese circuits are connected, for example, to fluorescent lamps,the'operator will hold the ychain in its extreme position of movementuntil `the lamps have begun to burn without flickering. He willthereupon release the pull-chain and the Vparts will be brought'by thespring 55 into the position shown in Figs. l Vand 3. During this `returnmovement, the toothed wheel 31 is returned with the shaft to itsoriginal position in which contact Vmembers 36dV engagel the 4insulatingsurfaces of the wheel. The auxiliary or starting circuits for the lamps-are now broken, the making and breaking ofthese circuits thus occurringduring a single actuation of thev chain.

The disc 43, however, does not return with'the shaft but remains in itsshifted position, the pawls 58 riding out of the openings 59 and passingin reverse direction into the nextv pair of diametricallyv disposedopenings A51|. The friction between the disc 43 and the shaft, coupledwith the friction between the contacts 54 and the wheel 45 is suflicientto prevent rearward slipping of the disc 43-'as the pawls 58 -pass overthe ratchet wheel 44 to their original position. Where necessary, aholding pawlor a friction element may be provided to insure againstreturn of the'wheel 43 although'I have found in certain commercialdevices constructed by me that this is not necessary. vIt willv thus beseen This will close the circuits in which the" that the disc f43 andtheparts attached'thereto Ywill Ibe rotatedstep-wise in the samedirection upon repeated actuation of the chain 56. When, therefore, thestarting circuits of the florescent lamps are broken upon release of thechain 56, the contacts 54 remain in engagement with the contact surfaces500i the bridge member 49, so that the -main operating circuits for' thelamps remain closed.l Uponthenext actuation of the chain, theseoperating circuits will be broken, as will be readilyunderstood. e

It will be seen from the foregoing that accordingtto the presentinvention there is provided anextremely compactv switch construction inwhich the actuating mechanism is positioned within a mountingmemben-which at the same time provides the stops (edges 10) for limitingthe movement of the actuating mechanism in opposite directions, and isconstructed for connection ina convenient manner with separate switchhousings whose switch mechanisms may each comprisea plurality ofcircuits which are opened and' closed according to different plans. Theparts are few in number and can be easily manufactured Yby `stamping ormolding. The different switch mechanisms are completely insulated fromeach other and from the actuating device so that the danger of shortcircuiting is eliminated.

The mounting member 22 itself serves also as an effective cover fortheactuating mechanism housed within it,.as it subtends more than of theYperiphery of the switch. The exposed portion of the central section Vofthe switch may be closed by means of a sheet metal plate 14 providedwith curved ends which flt about the stems ofthe screws 29.Y The plateis placed in position during the assembly of the switch prior to theinsertion'of the screws through the housing 2l and is held inposition-with theaid of its hooked end portions 15.

The housings are preferably provided with flat faces 15 for conveniencein mounting. The metallic cover plate 14 may be provided with a widenedVcentra1 portion 11 (Fig. 5) which engages and overlaps the rearsurfaces 16.

In the embodiment ofthe invention illustrated in Fig. 10, partssimilarto those'heretofore described Vare similarly numbered. Theconstruction shown in this figure is, in fact, identical with that showninY Fig. 2, except that the shaft 30 has been extended through the coverplate 55 in order to receive a second toothed wheel 31 which is housedin a second housing 2|. The arrangement of the contacts and theirsequence of operation in this construction may be the same as ordifferent from those described in connection with Figs. l to 8.V Fig. 10illustrates the ease with which the switch construction of the presentinvention lends itself to the addition of further switch units of moreor less standardized construction for the operation of additionalcircuits of the same or different characteristics from thosecontrolledby the switch mechanism within the housings immediatelyattached to the mounting member 22. It will be noted that all theseswitch mechanisms are actuated from one and the `same operating devicehoused within the mounting member 22. It is believed that theconstruction and operation of the mechanism shown in Fig. 10 will beobvious from the detailed description hereinabove.

Figs. 11 to l5 illustrate aconstruction in which all the bridgingmembers move step by step in the same direction upon operation of theactuating mechanism. Thestructure in effect in- ,volv'es the use of adisc 43 and associated parts as shown in Figs. 6 and 7 with theYdifference that the central aperture of the disc is non-.circular sothat the disc is lockedto the shaft and Arotates therewith. Theactuating mechanism, on the other hand, and particularlythe member ,57awhich carries the pawls 58 is free to move relatively tothe shaft 30 andto this vend is provided with a circular central opening 60a in contrastto the non-circular 'opening of the member illustrated in Fig. 8. Theoperation of this form of invention will be clear from the foregoing, itbeingplain that the member 51a oscillates within a limited angle ofmovement while the shaft and the` disc 43 mounted thereon moveprogressively inthe same direction so that the connection between thecontacts 54 is closed through the bridge member 49 during one actuationof the switch, and becomes broken on the next actuation thereof.

It will be apparent that any convenient number of housings 20 or 2lmaybe assembled upon a single mounting member 22 with the aid of screws29 of appropriate length, and that any type of circuits can becontrolled by the switch.-

Thus the Various circuit combinations described in the patent to Popp,No. 2,158,084 and likewise other combinations, can be incorporated inthe mechanism described hereinabove. The mechanism above described isequally well adapted for use in 2-way, 3-way, and 4-way switches. Anystandard type of switch can be associated with the manually controlledtime switch above described, as will be evident to those skilled in theart. Also it is not essential that the various discs or toothed wheelsbe arranged with their teeth in phase; on the contrary, one disc can beadvanced with respect to the other or others, and the discs may havedifferent numbers of teeth cooperating with different numbers ofterminals Within the separate individual housings or within a commonhousing` While the actuating mechanism has been illustrated by Way ofexample as being constituted of a pull-chain mechanism, it is obviousthat other known devices for oscillating or continuously rotating theshaft can be used; thus, a hand operated knob could be mounted upon anextended end of the shaft, or a push-button could be employed with anolf-center pawl, which reciprocates under the action of the finger ofthe operator and of a return spring and which engages a ratchet wheelassociated with the shaft.

As already indicated, the edges 10 of the mounting member 22 may serveas stops for limiting the angular movement of the actuating pawl member.To this end the legs of the mounting member are made of such length withreference to the axis of the shaft passing through the member that theangular movement of the pawl member is limited to 90 plus a certainangle of play, which may be 30 or thereabouts.

It will also be clear that the shaft itself may either be arranged foroscillation or for stepwise rotation continuously in the same direction.The different bridge members will of course be so mounted on the shaftthat the desired type or sequence of connection and disconnection issecured. Thus, where the shaft rotates stepwise in the same directionand the device is to include a manually controlled time switch, thetoothed wheel for such time switch could be secured to the operatingpawl and both such parts mounted to move freely on the shaft, that is,rotate relatively thereto, the spring acting to return these partstotheir initial position after actuation thereof..

'It will be obvious that where my time switch is inserted within theshort-circuiting line connecting the electrodes of-a iiuorescent lamp,such switch can be held closed until sputtering has ceased andthe lampis able to rcontinue on its operating circuit upon opening of theshort-circuiting switch. The illustrated mechanism can be easily adaptedforthe control of multiple filament bulbs, a plurality of motors, or aplurality of windings on the same motor, and in various other circuitcombinations. The switch can be so mounted as to be completely concealedexcept for the nipple through which the pull-chain, or any otherselected operating mechanism, passes.

It willbe evident, finally, that by the use of the individual housingsections and the selection of suitable bridge members, variouscombinations of multiple switches operated from a single actuating meanscan readily be assembled with a relatively few standardized parts. Thusthe same housings can be employed with bridge members whose contacts areconnected in different ways; and also withl bridge members which aremounted for continuous rotation in the same direction or foroscillation. As the assembly of the parts is both simple and rapid, theswitch parts can be kept in stock in knocked-down condition and ordersfor any particular type of switch combinations can be quickly lled.

Various parts of the invention above described may be used withoutothers without departing from the spirit or scope of the invention as.defined in the appended claims. Thus my novel mounting member can beassociated only with switch mechanisms operating in the conventionalway, that is, with connection and disconnection only upon successiveactuations of the switch; also, while the use of separate housingsections is desirable, the switch terminals and the bridge members mayall be positioned within a common housing.

Certain features of the present invention not claimed herein are claimedin my continuationin-part application, Serial No. 423,285, filedDecember 1'7, 1941.

I claim:

1. In an electric switch, a bridge member comprising a wheel made ofinsulating material and provided with a plurality of cam teeth upon itsperiphery, the cam surfaces increasing in radial dimension along theirperipheral extension measured from the center oi the wheel, and contactmembers upon only the portion of the cam surfaces of larger radius of atleast certain of the teeth and projecting beyond such portions so as tooverhang at least a portion of the adjacent insulating surface ofsmaller radius of the adjoining tooth, stationary contacts Whose freeends are arranged to engage the insulating and conducting surfaces ofsaid certain teeth in alternation, means for rotating said memberthrough a limited angle smaller than the angle subtended by one of saidcertain teeth and the projecting portion of its contact member, andmeans for returning said bridge member to its initial position, eachstationary contact thus playing permanently over the insulating andconducting surfaces of only one of the cam teeth of said member, andsaid projecting portions of the contact members insuring againstdropping of a stationary contact onto the next tooth.

2. A bridge member for electric switches comjpri'singa Wheel made ofinsulating material alnd provided witha plurality lof'c'am teeth`uponits lperiphery, the cam surfaces increasing inradial diniensionalongtheir Vperipheral extensin 'Ineas-V ured from the center of the wheel,and contact Amembers upon only vthe portion of the cam sur- ,face'svoflarger radius of at least certain of the teeth and projecting beyondsuch portions so as ,to overhang at leasta portion of the adjacentinsulating surface of 'smaller radius of the adjoining tooth, aconducting connection between the pair orpairsof contacts-stationarycontacts Whose free ends` are arranged Vto engage the insulating .andconducting surfaces of said certain teeth in alternation, means forrotating said member through a limited angle smaller than the anglesubtended by onenof said. certain teeth and the projecting portion ofitsV contact member, and 4 means for Vreturning said bridge member toits .initialpositiom each stationary contact thus playing permanentlyover the insulating and conducting surfaces of only one of the cam teethof said member, andV said projecting portions of the contact membersinsuring 'against dropping of a I'stationary contact onto the nexttooth.

asso-,eee

3. A bridge member for electric Switches com prisng a Wheelmade ofinsulating material and proyded Withapluralityof cam teeth uponv itsperiphery'whichare eccentric with respect to the centerof the Wheel,there'being an approximately radially extendingshoulder connecting thea'jacent cam surfaces; and contact' members u on only the portion of the'cam surfaces oflarger distance from the Wheel center'ofV certain of s idteeth and projecting beyond the adjacent shoulders soV as to overhangatleast a portion of the adjacent insulating surface of smaller distancefrom'the wheel center of the adjoining tooth, and

a'c'onducting comnectionbetween the pair orpairs of' contacts, saidbridge member being adaptedto be oscillated through an angle which issmaller,

than that subtended by a tooth with its overhang 'but which is greaterthan'that subtended by th

